1. Field of the Invention
The present invention relates to a display system for a work vehicle having at least one kind of Power Take Off (PTO) mode.
2. Description of the Related Art
A display system for a tractor having a PTO shaft is disclosed in US 2010/0191404A1. This tractor includes a rotation speed sensor for detecting a rotation speed of an engine and a tachometer for displaying an engine rotation speed detected by this rotation speed sensor. The tractor further includes a rotation speed sensor for detecting a rotation speed of the PTO shaft. The document however fails to disclose a function of displaying a detected PTO shaft rotation speed.
A tractor having the function of displaying an engine rotation speed and a PTO rotation speed is also known. For instance, the Japanese Unexamined Patent Application Publication No. 6-153610 (see paragraphs [0013], [0015], FIG. 1, FIG. 3) discloses a tractor having a rotation speed sensor for detecting a rotation speed of an engine. An engine rotation speed detected by this rotation speed sensor is displayed on a tachometer and a PTO rotation speed obtained by calculation of the detection result of the engine rotation speed is displayed on a PTO rotation speed indicating meter. Further, when a PTO clutch is disengaged, no input is made to the PTO rotation speed indicating meter. Moreover, the JP No. 6-153610 discloses, in its FIG. 3, a meter displaying both an engine rotation speed and a PTO rotation speed by pointers. From this meter, both an engine rotation speed and a PTO rotation speed can be read out. However, since a displaying scale for the engine rotation speed and a displaying scale for the PTO rotation speed are arranged on concentric arcs, the display area of the inner side scale (PTO rotation speed scale) is small, which makes accurate reading of the rotation speed difficult.
In view of the state of the art described above, there is a need for a display system that allows easy reading of both an engine rotation speed and a PTO rotation speed.